Simplify WebUI data sources. Currently WebUI data sources implement a URLDataSourceDelegate interfa…

chrome/browser/ui/webui/chrome_url_data_manager.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_WEBUI_CHROME_URL_DATA_MANAGER_H_
 #define CHROME_BROWSER_UI_WEBUI_CHROME_URL_DATA_MANAGER_H_
 
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/sequenced_task_runner_helpers.h"
 #include "base/synchronization/lock.h"
 #include "chrome/browser/profiles/profile_keyed_service.h"
 
 class ChromeURLDataManagerBackend;
 class MessageLoop;
 class Profile;
 
 namespace base {
-class DictionaryValue;
 class RefCountedMemory;
 }
 
 namespace content {
-class URLDataSourceDelegate;
+class URLDataSource;
 }
 
-class URLDataSource;
+class URLDataSourceImpl;
 
 // To serve dynamic data off of chrome: URLs, implement the
 // ChromeURLDataManager::DataSource interface and register your handler
 // with AddDataSource. DataSources must be added on the UI thread (they are also
 // deleted on the UI thread). Internally the DataSources are maintained by
 // ChromeURLDataManagerBackend, see it for details.
 class ChromeURLDataManager : public ProfileKeyedService {
  public:
   explicit ChromeURLDataManager(
       const base::Callback<ChromeURLDataManagerBackend*(void)>& backend);
   virtual ~ChromeURLDataManager();
 
   // Adds a DataSource to the collection of data sources. This *must* be invoked
   // on the UI thread.
   //
   // If |AddDataSource| is called more than once for a particular name it will
   // release the old |DataSource|, most likely resulting in it getting deleted
   // as there are no other references to it. |DataSource| uses the
   // |DeleteOnUIThread| trait to insure that the destructor is called on the UI
   // thread. This is necessary as some |DataSource|s notably |FileIconSource|
   // and |FaviconSource|, have members that will DCHECK if they are not
   // destructed in the same thread as they are constructed (the UI thread).
-  void AddDataSource(URLDataSource* source);
+  void AddDataSource(URLDataSourceImpl* source);
 
   // Deletes any data sources no longer referenced. This is normally invoked
   // for you, but can be invoked to force deletion (such as during shutdown).
   static void DeleteDataSources();
 
   // Convenience wrapper function to add |source| to |profile|'s
-  // |ChromeURLDataManager|.
+  // |ChromeURLDataManager|. Creates a URLDataSourceImpl to wrap the given
+  // source.
   static void AddDataSource(Profile* profile,
-                            content::URLDataSourceDelegate* delegate);
+                            content::URLDataSource* source);
+
+  // Like above, but takes a URLDataSourceImpl directly.
+  static void AddDataSourceImpl(Profile* profile,
+                                URLDataSourceImpl* source);
 
  private:
-  friend class URLDataSource;
+  friend class URLDataSourceImpl;
   friend struct DeleteURLDataSource;
-  typedef std::vector<const URLDataSource*> URLDataSources;
+  typedef std::vector<const URLDataSourceImpl*> URLDataSources;
 
   // If invoked on the UI thread the DataSource is deleted immediatlye,
   // otherwise it is added to |data_sources_| and a task is scheduled to handle
   // deletion on the UI thread. See note abouve DeleteDataSource for more info.
-  static void DeleteDataSource(const URLDataSource* data_source);
+  static void DeleteDataSource(const URLDataSourceImpl* data_source);
 
   // Returns true if |data_source| is scheduled for deletion (|DeleteDataSource|
   // was invoked).
-  static bool IsScheduledForDeletion(const URLDataSource* data_source);
+  static bool IsScheduledForDeletion(const URLDataSourceImpl* data_source);
 
   // A callback that returns the ChromeURLDataManagerBackend. Only accessible on
   // the IO thread. This is necessary because ChromeURLDataManager is created on
   // the UI thread, but ChromeURLDataManagerBackend lives on the IO thread.
   const base::Callback<ChromeURLDataManagerBackend*(void)> backend_;
 
   // |data_sources_| that are no longer referenced and scheduled for deletion.
   // Protected by g_delete_lock in the .cc file.
   static URLDataSources* data_sources_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeURLDataManager);
 };
 
 // Trait used to handle deleting a URLDataSource. Deletion happens on the UI
 // thread.
 //
 // Implementation note: the normal shutdown sequence is for the UI loop to
 // stop pumping events then the IO loop and thread are stopped. When the
 // URLDataSources are no longer referenced (which happens when IO thread stops)
 // they get added to the UI message loop for deletion. But because the UI loop
 // has stopped by the time this happens the URLDataSources would be leaked.
 //
 // To make sure URLDataSources are properly deleted ChromeURLDataManager manages
 // deletion of the URLDataSources.  When a URLDataSource is no longer referenced
 // it is added to |data_sources_| and a task is posted to the UI thread to
 // handle the actual deletion. During shutdown |DeleteDataSources| is invoked so
 // that all pending URLDataSources are properly deleted.
 struct DeleteURLDataSource {
-  static void Destruct(const URLDataSource* data_source) {
+  static void Destruct(const URLDataSourceImpl* data_source) {
     ChromeURLDataManager::DeleteDataSource(data_source);
   }
 };
 
 // A URLDataSource is an object that can answer requests for data
 // asynchronously. URLDataSources are collectively owned with refcounting smart
 // pointers and should never be deleted on the IO thread, since their calls
 // are handled almost always on the UI thread and there's a possibility of a
 // data race.  The |DeleteDataSource| trait above is used to enforce this.
-//
-// A delegate of URLDataSource should handle calls to StartDataRequest() by
-// starting its (implementation-specific) asynchronous request for the data,
-// then call SendResponse() to notify.
-class URLDataSource : public base::RefCountedThreadSafe<
-    URLDataSource, DeleteURLDataSource> {
+class URLDataSourceImpl : public base::RefCountedThreadSafe<
+    URLDataSourceImpl, DeleteURLDataSource> {
  public:
   // See source_name_ below for docs on that parameter. Takes ownership of
-  // |delegate|.
-  URLDataSource(const std::string& source_name,
-                content::URLDataSourceDelegate* delegate);
+  // |source|.
+  URLDataSourceImpl(const std::string& source_name,
+                    content::URLDataSource* source);
 
   // Report that a request has resulted in the data |bytes|.
   // If the request can't be satisfied, pass NULL for |bytes| to indicate
   // the request is over.
   virtual void SendResponse(int request_id, base::RefCountedMemory* bytes);
 
   const std::string& source_name() const { return source_name_; }
-  content::URLDataSourceDelegate* delegate() const { return delegate_.get(); }
-
-  static void SetFontAndTextDirection(
-      base::DictionaryValue* localized_strings);
+  content::URLDataSource* source() const { return source_.get(); }
 
  protected:
-  virtual ~URLDataSource();
-
-  content::URLDataSourceDelegate* release_delegate() {
-    return delegate_.release();
-  }
+  virtual ~URLDataSourceImpl();
 
  private:
   friend class ChromeURLDataManagerBackend;
   friend class ChromeURLDataManager;
-  friend class base::DeleteHelper<URLDataSource>;
+  friend class base::DeleteHelper<URLDataSourceImpl>;
 
   // SendResponse invokes this on the IO thread. Notifies the backend to
   // handle the actual work of sending the data.
   virtual void SendResponseOnIOThread(
       int request_id,
       scoped_refptr<base::RefCountedMemory> bytes);
 
   // The name of this source.
   // E.g., for favicons, this could be "favicon", which results in paths for
   // specific resources like "favicon/34" getting sent to this source.
   const std::string source_name_;
 
   // This field is set and maintained by ChromeURLDataManagerBackend. It is
   // set when the DataSource is added, and unset if the DataSource is removed.
   // A DataSource can be removed in two ways: the ChromeURLDataManagerBackend
   // is deleted, or another DataSource is registered with the same
   // name. backend_ should only be accessed on the IO thread.
   // This reference can't be via a scoped_refptr else there would be a cycle
   // between the backend and data source.
   ChromeURLDataManagerBackend* backend_;
 
-  scoped_ptr<content::URLDataSourceDelegate> delegate_;
+  scoped_ptr<content::URLDataSource> source_;
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CHROME_URL_DATA_MANAGER_H_